Support arm



FIG. 1 is a perspective view of my support arm;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a left side elevational view thereof; and,

FIG. 7 is a right side elevational view thereof.

The Allen wrench attached to the mounting plate of the support arm shown in broken lines in FIGS. 3, 4, 5, 6, and 7 form no part of the claimed design. Also, recesses formed in the mounting plate shown in broken lines in FIGS. 1 and 2 form no part of the claimed design. Further, the ribbing shown in broken lines in FIG. 5 forms no part of the claimed design. 

The ornamental design for a support arm, as shown and described. 